Welcome to PostGIS in Action, Third Edition. PostGIS is a spatial database extender for the PostgreSQL database management system. This book will teach you the fundamentals of spatial databases in general, key concepts in geographic information systems (GIS), and more specifically how to configure, load, and query a PostGIS-enabled database. You’ll learn how to perform actions with single lines of SQL code that you thought were possible only with a desktop GIS system. By using spatial SQL, much of the heavy lifting that would require many manual steps in desktop GIS tools can be scripted and automated.
This book is divided into three sections and four appendixes. Part 1 covers the fundamentals of spatial databases, GIS, and working with spatial data. Although part 1 is focused on PostGIS, many of the concepts you’ll learn in this part are equally applicable to other spatial relational databases.
Chapter 1 covers the fundamentals of spatial databases and what you can do with a spatially enabled database that you can’t do with a standard relational database. It also introduces features that are fairly unique to PostGIS. It concludes with a fast-paced example of loading fast-food restaurant longitude/latitude data and converting it to geometric points, loading road data from Esri shapefiles, and doing spatial summaries by joining these two sets of data.